Due to the depletion of fossil fuels and the concerns regarding the environmental impacts of fossil fuel burning, there is a need for rapid development of production methods for sustainable fuels including biofuels replacing fossil fuels.
Methods for the production of so called first generation biofuel have been developed, but have the disadvantage of using feedstock such as sugar, starch, vegetable oil, or animal fats, which are derived from food crops or animals that may have more useful purposes than fuel production.
For example WO 2004/035714 describes a method for the production of a first generation biofuel, where a plant or animal oil is contacted with an acid catalyst, such as a zeolite, creating an oil-catalyst mixture. The mixture is subjected to microwave energy thereby producing biofuels via a catalyzed transesterification process.
Second generation biofuel production processes can use a variety of non food crops. These include waste biomass, the stalks of wheat, barley, corn, wood, and special energy- or biomass crops. Many second generation biofuels are under development such as biohydrogen, biomethanol, biodiesel, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel. The production of second generation biofuels may use biological or thermal depolymerisation of the biomass material to obtain the fuel. For thermal depolymerisation the additional use of chemical catalysts provides for a more efficient depolymerisation process, via a Thermo Catalytic Depolymerisation Process (TCDP). Heating may for some feedstocks be provided by microwave energy.
Thus, WO 2009/067266 describes a method of manufacturing diesel, comprising the steps of providing a feedstock, processing the feedstock to provide hydrogen deficient carbon and first volatiles, using superheated natural gas at a temperature between 1000-1500° F. (537-816° C.) and subsequently hydrogenating the hydrogen deficient carbon material followed by processing the hydrogen deficient carbon material into second volatiles and diesel. In one embodiment the processing of the activated carbon into diesel is performed using depolymerisation and polymerization with microwave heating and a zeolite catalyst.
WO 2009/010435, U.S. Pat. No. 6,184,427 and CN 20071069214 all describe methods of converting plastic waste materials comprising various polyethylenes into lighter hydrocarbons using microwave energy and various catalyst. None of the processes are for the production of biofuel. Also, WO 2009/010435 is a process performed in aquous solution, and is unsuitable for production of biofuels, and no experimental data is presented for a aluminosilicate based catalyst. U.S. Pat. No. 6,184,427 uses both sentizisers and catalysts in relatively large amounts starting from 30% and upwards. CN 20071069214 does not used aluminosilicate based catalysts.
The above methods for the production of biofuel require significant processing of the raw feedstock material prior to processing it into biofuel, i.e. by either extraction of oil residues from plants or animals, or activation of feedstock into hydrogen deficient carbon using superheated gas. Hence, an improved process for the production of biofuel would be advantageous, and in particular a more high-yielding and energy efficient process where a feedstock is converted into biofuel would be advantageous.